The present invention generally relates to methods and devices which are used for the production of oil and natural gas. More specifically, this invention is directed to methods and devices which provide for the temporary production and measurement of multiple-phase fluid streams in the absence, incapacity, or malfunction of permanent flow lines and measuring systems. The disclosed invention may be used where the length of the required temporary flow line is relatively long; for example where the distance between the wellhead and nearest production flow line or inlet to surface facilities is over 1000 feet in length.
The purpose of the present invention is to provide a method and apparatus for the transport and/or measurement of oil and gas from an oil and gas well for a number of different situations the oil and gas operator may face. Included within these situations are the following scenarios:
(1) The production flow lines have been disconnected for a variety of reasons, such as low production from the well or lack of integrity of the flow line.
(2) A gas well has died from loading up with liquids, such that insufficient wellhead pressure exists to produce well fluids into the flow line system.
(3) A new well is ready to be placed on production, but the permanent flow lines between the wellhead and surface facilities have yet to be installed.
(4) The operator desires, for various reasons, to produce fluids from the tubing-casing annulus which fluids the operator desires to measure before placing in the existing surface facilities, or where the operator desires to direct those fluids to a higher pressure system. This situation includes instances where the operator circulates fluids down the tubing string and produces fluids from the tubing-casing annulus.
In the case of idle wells where the flow lines have been disconnected, it is known that oil, gas and other reservoir fluids may gradually accumulate at the wellhead as the pressure within the wellbore approaches static pressure. As the wellbore reaches static pressure, a column of gas, oil, and/or water may build up in the tubing and in the tubing-casing annulus, to where an appreciable volume of hydrocarbons may accumulate at the wellhead at ground surface. Gas expansion may result in these accumulated fluids exerting substantial surface pressures at the wellhead in the tubing-casing annulus. Unless there are readily available production facilities designed for receiving these fluids, recovery of these potentially valuable substances is difficult.
In the past when there were no restrictions on venting gas to the atmosphere, an operator could simply bleed the accumulated gas from the tubing-casing annulus and suction the accumulated oil into a vacuum truck. However, regulatory, environmental and economic factors render this option illegal, undesirable and wasteful. The disclosed method and apparatus solves this problem and provides means by which the producer may be able to get the well back on production or reclaim oil and gas that is otherwise not available.
In the case of loaded up gas wells, there may be insufficient tubing head pressure to produce the loaded up well into the gas production system. The present invention provides a means for producing the well into a system with no back-pressure, separating the liquids from the gas phase, and compressing the gas to sufficient pressure for delivery into the gas production system.
In the case of new wells, it is often desirable to place the new well on production as soon as possible following completion to allow the well to clean-up or to obtain an initial well test. However, placing the well on production may be delayed if a flow line has not been installed between the wellhead and production facility. The disclosed invention provides a rapid means of linking the wellhead to the production system, and placing a well immediately into test.
In some cases the operator may desire to pump fluids down the tubing and take returns from the tubing-casing annulus, which, in normal operation, provides a conduit for gas production. For example, an operator may wish to pump scale inhibitor down the tubing and take returns on the tubing-casing annulus, without the returns going directly into the gas production system. It may be desirable to meter the returns. The disclosed method and apparatus allows the operator to achieve these objectives.
The present invention is directed to a method and apparatus which meets the needs identified above. The components of the disclosed apparatus may be mounted on a flatbed gooseneck trailer, thereby allowing the apparatus to be readily transportable to an oil well location for recovery of oil and gas, for the testing of the wells, or for other desired well operations. Alternatively, the components of the disclosed apparatus may be mounted on a crane-liftable skid unit where access to a well location is not practical by trailer.
The present invention comprises a portable flowline and measuring unit for delivering fluids from an oil well to a production facility, where the oil well has fluid conducting means for conducting fluids from the oil well to the portable flowline and measuring unit. The flowline and measuring unit comprises a flatbed trailer, the trailer having a platform, towing means and wheels, the platform comprising a top side and a bottom side, and wheels attached to the bottom side.
The top side of the platform comprises a production assembly. The production assembly includes components for reducing the pressure of the fluid stream, such as a choke valve hydraulically connected to the fluid conducting means. Inlet piping connects the choke valve to a two-phase separator. The two-phase separator comprises a gas outlet and a liquid outlet. The two-phase separator further comprises high liquid level detection means and low liquid level detection means. The high liquid level detection means produce a first signal when the liquid level in the two-phase separator reaches a first position. The low liquid level detection means produce a second signal when the liquid level in the two-phase separator reaches a second lower position.
Gas outlet piping is attached to the gas outlet, with the gas outlet piping hydraulically connected to gas discharge means, such as a separate gas production line, a flexible flowline contained on the unit, or a flare. A backpressure regulator is hydraulically connected to the gas outlet piping.
Liquid outlet piping is attached to the liquid outlet of the two-phase separator. A control dump valve is hydraulically connected to the liquid outlet piping. The control dump valve comprises a discharge outlet, and means for receiving the first signal and the second signal from the high liquid level detection means and the low liquid level detection means. The control dump valve also comprises means for actuating the valve, the dump valve opening upon receiving the first signal and closing upon receiving the second signal.
The unit further comprises a spooling drum and power means for rotating the spooling drum. A flexible flowline is wrapped around the spooling drum, where the flexible flowline has a first end and a second end. The discharge outlet of the dump valve is hydraulically connected to the first end of the flexible flowline. The second end of the flexible flowline has connecting means adapted to hydraulically connect to the production facility.
The unit may further comprise a liquid recirculating valve which is hydraulically connected to the liquid outlet piping. The recirculating valve is connected to a return line connected to the two-phase separator. The recirculating valve has means for receiving the first signal and the second signal and means for actuating the recirculating valve. The liquid recirculating valve closes when it receives the first signal and opens when it receives the second signal.
The unit may also comprise means for measuring the liquid flow rate and the gas flow rate.
Methods of using the disclosed apparatus are also disclosed. A newly drilled well having no permanent production line installed may be temporarily produced through the disclosed unit. This method comprises attaching the first end of a fluid-bearing conduit to the oil well. The second end of the fluid bearing conduit is connected to the portable flowline and gas measuring unit. The second end of the flexible flowline is attached to the production facility and the well is opened to allow reservoir fluids, including hydrocarbons, to flow through the portable flowline and gas measuring unit into the production facility. This method allows a newly drilled well to be produced and tested quickly, without having to await the installation of a permanent flowline or measurement facilities.